La(OTf)₃: An Efficient Promoter for Thioglycoside Activation in Conjunction with N-Iodosuccinimide

Abstract

Use of La(OTf)₃ as a Lewis acid promoter for N-iodosuccinimide-mediated activation of thioglycosides is reported. The glycosylation reactions proceeded smoothly with good to excellent yields and stereoselectivity.

Key words

thioglycoside - glycosylation - disarmed donor - Lewis acid - NIS

References and Notes

• 1a Baeschlin DK. Green LG. Hahn MG. Hinzen B. Ince SJ. Ley SV. Tetrahedron: Asymmetry  2000,  11:  173 
• 1b Kanie O. Ito Y. Ogawa T. J. Am. Chem. Soc.  1994,  116:  12073 
• 1c Fraser-Reid B. Udodong UE. Wu ZF. Ottosson H. Merritt JR. Rao CS. Roberts C. Madsen R. Synlett  1992,  927 
• 1d Veeneman GH. van Boom JH. Tetrahedron Lett.  1990,  31:  275 
• 1e For a review, see: Yu B. Yang ZY. Cao HZ. Curr. Org. Chem.  2005,  9:  179 
• 2a Plante OJ. Palmacci ER. Seeberger PH. Adv. Carbohydr. Chem. Biochem.  2003,  58:  35 
• 2b Plante OJ. Palmacci ER. Seeberger PH. Science  2001,  291:  1523 
• 3a Fügedi P. Garegg PJ. Lönn H. Norberg T. Glycoconjugate J.  1987,  4:  97 
• 3b Garegg PJ. Adv. Carbohydr. Chem. Biochem.  1997,  52:  179 
• 4a Fügedi P. In The Organic Chemistry of Sugars   Levy DE. Fügedi P. CRC Press; Boca Raton: 2005.  p.181 
• 4b Demchenko AV. Lett. Org. Chem.  2005,  2:  580 
• 4c Boons G.-J. Tetrahedron  1996,  52:  1095 
• 5a Ferrier RJ. Hay RW. Vethaviyasar N. Carbohydr. Res.  1973,  27:  55 
• 5b Mukaiyama T. Nakatsuka T. Shoda S. Chem. Lett.  1979,  487 
• 5c Hanessian S. Bacquet C. Lehong N. Carbohydr. Res.  1980,  80:  C17 
• 5d Woodward RB. Logusch E. Nambiar KP. Sakan K. Ward DE. Au-Yeung BW. Balaram P. Browne LJ. Card PJ. Chen CH. J. Am. Chem. Soc.  1981,  103:  3215 
• 5e Garegg PJ. Henrichson C. Norberg T. Carbohydr. Res.  1983,  116:  162 
• 6a Fügedi P. Garegg PJ. Carbohydr. Res.  1986,  149:  C9 
• 6b Andersson F. Fügedi P. Garegg PJ. Nashed M. Tetrahedron Lett.  1986,  27:  3919 
• 7 Dasgupta F. Garegg PJ. Carbohydr. Res.  1988,  177:  C13 
• 8a Martichonok V. Whitesides GM. J. Org. Chem.  1996,  61:  1702 
• 8b Crich D. Sun S. Tetrahedron  1998,  54:  8321 
• 9 Shimizu H. Ito Y. Ogawa T. Synlett  1994,  535 
• 10 Jona H. Takeuchi K. Saitoh T. Mukaiyama T. Chem. Lett.  2000,  1178 
• 11 Durón SG. Polat T. Wong C.-H. Org. Lett.  2004,  6:  839 
• 12 Crich D. Smith M. J. Am. Chem. Soc.  2001,  123:  9015 
• 13 Wang C. Wang H. Huang X. Zhang L.-H. Ye X.-S. Synlett  2006,  2846 
• 14 Codée JDC. Nitjens REJN. den Heeten R. Overkleeft HS. van Boom JH. van der Marel GA. Org. Lett.  2003,  5:  1519 
• 15 Tatai J. Fügedi P. Org. Lett.  2007,  9:  4647 
• 16 Veeneman GH. van Leeuwen SH. van Boom JH. Tetrahedron Lett.  1990,  31:  1331 
• 17 Konradsson P. Mootoo DR. McDevitt RE. Fraser-Reid B. J. Chem. Soc., Chem. Commun.  1990,  270 
• 18 Mukhopadhyay B. Collet B. Field RA. Tetrahedron Lett.  2005,  46:  5923 
• 19a Roy B. Pramanik K. Mukhopadhyay B. Glycoconjugate J.  2008,  25:  157 
• 19b Dasgupta S. Pramanik K. Mukhopadhyay B. Tetrahedron  2007,  63:  12310 
• 19c Mandal S. Mukhopadhyay B. Tetrahedron  2007,  63:  11363 
• 19d Dasgupta S. Mukhopadhyay B. Eur. J. Org. Chem.  2008,  34:  5770 
• 19e Verma PR. Mukhopadhyay B. Carbohydr. Res.  2010,  345:  432 
• 19f Roy B. Field RA. Mukhopadhyay B. Carbohydr. Res.  2009,  344:  2311 
• 19g Verma P. Mukhopadhyay B. Carbohydr. Res.  2009,  344:  2554 
• 20 Dasgupta S. Rajput VK. Roy B. Mukhopadhyay B.
  J. Carbohydr. Chem.  2007,  26:  91 
• 21 Schmidt RR. Michel J. Angew. Chem.  1980,  92:  763 
• 22 Konradsson P. Mootoo DR. McDevitt RE. Fraser-Reid B. J. Chem. Soc., Chem. Commun.  1990,  270 
• 23 Sakai J. Takeda T. Ogihara Y. Carbohydr. Res.  1981,  95:  125 
• 24 Mukhopadhyay B. Field RA. Carbohydr. Res.  2004,  339:  1285 
• 25 Rajput VK. Mukhopadhyay B. J. Org. Chem.  2008,  73:  6924 
• 26 Mandal S. Mukherjee S. Mukhopadhyay B. Mukherjee S. J. Carbohydr. Chem.  2010,  29:  133 
• 27 Mukhopadhyay B. Maurer SV. Rudolph N. Collet B. van Well R. Russell DA. Field RA. J. Org. Chem.  2005,  70:  9059 
• 28 Rajput VK. Mukhopadhyay B. Trends Carbohydr. Chem.  2010,  2:  5 

29

p -Methoxyphenyl 2,3-Di- O -benzoyl-4,6- O -benzylidene-β- D-glucopyranosyl-(1→3)-4- O -acetyl-2,6-di- O -benzyl-β- D-glucopyranoside (26): ^¹H NMR (CDCl₃, 500 MHz):
δ = 7.87, 7.83 (2 × d, 4 H, ArH), 7.38-7.13 (m, 21 H, ArH), 6.87, 6.68 (2 × d, 4 H, ArH), 5.67 (t, J = 9.5 Hz, 1 H, H-3′), 5.47 (s, 1 H, CHPh), 5.42 (d, J = 3.0 Hz, 1 H, H-4), 5.38 (dd, J = 8.0, 9.5 Hz, 1 H, H-2′), 5.17 (d, J = 8.0 Hz, 1 H, H-1′), 4.76 (d, J = 8.0 Hz, 1 H, H-1), 4.68 (d, J = 10.5 Hz, 1 H, CH₂Ph), 4.44, 4.40 (2 × d, J = 10.5 Hz, 2 H, CH₂Ph), 4.30 (d, J = 10.5 Hz, 1 H, CH₂Ph), 4.29 (m, 1 H, H-6a′), 3.92 (dd, J = 4.0, 9.5 Hz, 1 H, H-3), 3.89 (t, J = 9.5 Hz, 1 H, H-4′), 3.78 (m, 2 H, H-2, H-6b′), 3.68 (m, 2 H, H-4′, H-6a), 3.67 (s, 3 H, ArCH₃), 3.52 (m, 3 H, H-5, H-5′, H-6b), 2.11 (s, 3 H, COCH₃). ^¹³C NMR (CDCl₃, 500 MHz): δ = 170.4 (COCH₃), 165.6, 165.1 (2 × COPh), 155.4, 151.3, 137.8, 136.8, 133.3, 133.2, 129.8, 129.7, 129.4, 129.3 (2), 129.0, 128.5 (2), 128.4 (2), 128.3 (2), 128.2 (2), 128.0(2), 127.9 (2), 127.8 (2), 127.7 (2), 126.1 (2), 118.3 (2), 114.6 (2) (ArC), 102.7 (CHPh), 101.4 (C-1′), 101.1 (C-1), 79.4, 78.6, 76.2, 75.1, 73.8, 73.0, 71.9, 69.7, 68.7, 68.6, 66.5, 55.6 (ArCH₃), 20.8 (COCH₃). HRMS: m/z calcd for C₅₆H₅₄O₁₅Na [M + Na]⁺: 989.3360; found: 989.3354.

30

General procedure for glycosylation reactions: A mixture of acceptor (1.0 mmol), thioglycoside donor (1.2 mmol) and 4 Å MS in anhydrous CH₂Cl₂ (10 mL) was stirred under nitrogen for 30 min. La(OTf)₃ (0.3 mmol) was added and the mixture was stirred at 0 ˚C until TLC (n-hexane-EtOAc, 2:1) showed complete consumption of the starting material. The mixture was filtered through a pad of Celite and the filtrate was washed successively with aq Na₂S₂O₇ (2 × 20 mL), aq sat. NaHCO₃ (2 × 20 mL), and brine (20 mL). The organic layer was separated, dried (Na₂SO₄), filtered and evaporated in vacuo. The residue was purified by flash chromatography using a suitable mixture of
n-hexane-EtOAc as eluent to afford pure glycosylated products.